Composition and method for treating the surface of aluminiferous metals

ABSTRACT

Treatment of aluminiferous metal surfaces with an aqueous liquid composition which has a pH value in the range from 1.8 to 4.0 and comprises (A) from 0.01 to 1.0 g/L of phosphate ions, (B) from 0.01 to 0.5 g/L, measured as its total stoichiometric equivalent as metal, of water-soluble zirconium and titanium compounds, (C) from 0.01 to 2-0 g/L, measured as fluorine, of simple and/or complex fluoride anions; and (D) from 0.01 to 2.0 g/L of water-soluble polyamides that contain at least one tertiary amino or polyoxyalkylene moiety forms a highly corrosion-resistant, strongly paint-adherent, and low friction conversion coating on the metal surface.

FIELD OF THE INVENTION

This invention relates to a liquid composition, which may be either aworking composition suitable for direct use in treating metal (and if somay also be called a "bath" herein below even if not used by immersion)or a concentrate composition suitable for diluting with water and/ormixing with one or more other concentrate compositions to form a workingcomposition, and to a method for treating the surface of aluminiferousmetals, which are defined for this purpose to be aluminum and its alloysthat contain at least 45% by weight of aluminum. More particularly, thisinvention relates to a composition and/or method, for treating thesurface of aluminiferous metals, that imparts thereto an excellentresistance to blackening by boiling water, an excellent paint adherence,and an excellent lubricity, and which are therefore useful, for example,for creating surface conditions that are highly adapted for aluminum canfabrication.

DESCRIPTION OF RELATED ART

The manufacture of drawn-and-ironed (the phrase "drawn-and-ironed" andany grammatical variations thereof such as "drawing-and-ironing","draw-and-iron", or the like being hereinafter usually abbreviated "DI")aluminum cans typically performed by a DI process, followed by surfacecleaning with an acidic cleaner in order to remove soil commonly called"smut" in the art, the smut being composed of aluminum microparticles,lubricant (coolant), metal soap, and the like, and then by a phosphateconversion coating treatment on the surface, with the goal of improvingthe corrosion resistance and paint adherence. These conversion coatingtreatments may be broadly classified into chromate treatments, whichproduce chromium phosphate coatings, and non-chromate treatments, whichusually contain zirconium compounds such as fluozirconic acid and saltsthereof and produce composite films of zirconium oxide, zirconiumphosphate, and the like.

Cleaning processes using non-chromate conversion reagents have recentlycome to account for approximately 80% of the cleaning lines in Japan asa consequence of environmental protection issues. After the conversiontreatment, conversion-coated aluminum cans are generally subjected to athorough rinse in a washer and drying in a water-draining oven, and,upon exiting the oven, are transported to a printing or paintingprocess. Upon reaching the printing or painting process, the cans, whichduring previous process steps are typically running in about five tothirty lines, are passed through a single filer to form a single linefor transfer to a special-purpose conveyor. Can transport is impeded atthis point by the contact occurring between the cans and guides andbetween individual cans. The prevailing view is that the reason for thisis the relatively high coefficient of static friction of cleaned andconversion-treated aluminum cans. The recent increases in transportrates associated with increases in can manufacturing output have causeda proliferation in the sources of this problem, and the resultingreduction in productivity has become an increasingly serious problem.This has created a strong desire to reduce the coefficient of staticfriction of the external surfaces of aluminum cans without impairing thecorrosion resistance.

For example, Japanese Patent Application Laid Open Kokai or Unexamined!Number Sho 64-85292 85,292/1989! teaches a method for impartinglubricity to aluminum cans and thereby raising the can transportefficiency. In this method, a water-soluble organophosphate ester,water-soluble derivative of a saturated fatty acid, or the like issprayed onto the can surface between the final deionized water rinse inthe can washer line and the draining-drying process. This sprayingserves to form a lubricating organic film on the can surface.

However, when a cleaning unit is employed that recycles the deionizedwater from the final rinse using an active carbon adsorption treatment,components of the coating end up being adsorbed by the active carbon.This has negative economic consequences because it acceleratesdeterioration of the active carbon and increases chemical consumption.In addition, when the shape of the workpiece is such that the bath tendsto drain from one part of the workpiece surface into a pool over anotherpart of the surface, the concentration of the residual bath in the poolzones during drying causes such problems as uneven blotches and paintfilm delamination.

Japanese Patent Application Laid Open Kokai or Unexamined! Number Hei5-239434 239,434/1993! describes a method for forming a highlylubricating organic-inorganic composite coating. In this method, in theconversion coating process in the aforementioned can washer line thealuminiferous metal substrate is sprayed with or immersed in an acidicaqueous solution (pH adjusted to 2 to 5) that contains metal ions (Fe,Zr, Sn, Al, and/or Ce) and/or water-soluble organophosphate esters orwater-soluble derivatives of a saturated fatty acid. Nevertheless, thealuminiferous metal afforded by this method still does not exhibit anacceptable resistance to blackening.

In sum, then, there is not yet available at the present time acomposition and/or method for treating the surface of aluminiferousmetals that is able to simultaneously furnish an excellent corrosionresistance, excellent paint adherence, and excellent lubricity under allor almost all conditions of practical use of the treated aluminiferousmetal substrates.

DESCRIPTION OF THE INVENTION Problems to Be Solved by the Invention

The present invention seeks to solve the problems described above forthe related art. In specific terms, the present invention introduces anovel surface-treatment composition and/or method that is able to form avery corrosion-resistant, strongly paint-adherent, and highlylubricating conversion coating on the surface of aluminiferous metals.

SUMMARY OF THE INVENTION

It was discovered that very corrosion-resistant, stronglypaint-adherent, and highly lubricating coatings can be formed on thesurface of aluminiferous metals through the use of a water-basedtreatment bath containing particular quantities of phosphate ion,fluoride, water-soluble polyamide, and at least one selection fromwater-soluble zirconium and titanium compounds.

A composition according to the present invention, which may be either aworking composition directly suitable for treating the surface ofaluminiferous metals or a concentrate for making a working compositionby dilution with water and/or mixing with other concentrates, comprises,preferably consists essentially of, or more preferably consists of,water and:

(A) phosphate ions;

(B) a component selected from water-soluble zirconium and titaniumcompounds, in an amount such that the ratio by weight of thestoichiometric equivalent as total zirconium and titanium metal to theweight of phosphate ions in the composition is from 0.01 to 50;

(C) a component selected from simple and complex fluoride anions, in anamount such that the ratio by weight of the stoichiometric equivalent astotal fluorine to the weight of phosphate ions in the composition isfrom 0.01 to 200; and

(D) a component selected from polyamides that include moieties selectedfrom the group consisting of tertiary amino moieties and polyoxyalkylenemoieties, in an amount such that the ratio by weight of the polyamidesto the weight of phosphate ions in the composition is from 0.01 to 200.

A bath according to the present invention for treating the surface ofaluminiferous metals is an aqueous solution, with a pH value in therange from 1.8 to 4.0, which comprises, preferably consists essentiallyof, or more preferably consists of water and:

(A) from 0.01 to 1.0 grams per liter (hereinafter usually abbreviated"g/L") of phosphate ions,

(B) from 0.01 to 0.5 g/L, measured as its total stoichiometricequivalent as zirconium and/or titanium metal, of a component selectedfrom the group consisting of water-soluble zirconium and titaniumcompounds;

(C) from 0.01 to 2.0 g/L, measured as its stoichiometric equivalent asfluorine, of a component selected from the group consisting of simpleand complex fluoride anions; and

(D) from 0.01 to 2.0 g/L of a component selected from the groupconsisting of water-soluble polyamide molecules, each of which containsat least one moiety selected from the group consisting of tertiary aminemoieties and polyoxyalkylene moieties.

Finally, a method according to the present invention for treating asurface of aluminiferous metals characteristically comprises theformation of a conversion coating on a surface of aluminiferous metal bycontacting the metal surface with a surface-treatment bath according tothe invention as described above, in order to form thereon a layerincluding material incorporated from the surface-treatment bath and,optionally but preferably, thereafter rinsing with water and drying byheating.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (A) is a top view showing cans to be tested for coefficient offriction in place on a tiltable plate in testing apparatus. FIGS. 1 (B)and 1 (C) are front and side views respectively of the same apparatus,with cans in place thereon, as is shown in FIG. 1 (A).

DESCRIPTION OF PREFERRED EMBODIMENTS

Aluminiferous metals which may be subjected to the present inventionencompass aluminum and aluminum alloys, wherein said aluminum alloysencompass aluminum/manganese alloys, aluminum/magnesium alloys,aluminum/copper alloys, and the like. The shape and dimensions of thealuminiferous metal are not critical; for example, sheet, tubing, wire,and the like, may all be treated.

A concentrate composition according to the present invention is awaterbased mixture--and preferably an aqueous solution--containing thenecessary ingredients already described above. The total solidsconcentration in such as concentrate composition is not critical, but ingeneral preferably does not exceed 10 weight % and more preferably is0.01 to 1 weight %.

The phosphate ions source can be, for example, phosphoric acid (H₃ PO₄),sodium phosphate (Na₃ PO₄), ammonium phosphate ((NH₄)₃ PO₄), and/or thelike. The phosphate ions concentration preferably ranges from 0.01 to1.0 g/L and particularly preferably ranges from 0.02 to 0.40 g/L. Thereactivity, with a surface of aluminiferous metal, of a bath otherwiseaccording to the invention but with phosphate ions concentrations below0.01 g/L generally is inadequate, so that an acceptable coating will notbe produced. Since no additional improvements in film-forming capacityare obtained at phosphate ions concentrations beyond 1.0 g/L, thecorresponding increase in the cost of the treatment bath is economicallyunjustified.

The water-soluble zirconium compounds and water-soluble titaniumcompounds can be selected, for example, from oxides such as zirconiumoxide and titanium oxide, hydroxides such as zirconium hydroxide andtitanium hydroxide, fluorides such as zirconium fluoride and titaniumfluoride, and nitrates such as zirconium nitrate and titanium nitrate;however, other water-soluble compounds of zirconium and titanium may beused. The concentration of this component preferably ranges from 0.01 to0.5 g/L, measured as the stoichiometric equivalent as zirconium and/ortitanium metal, and particularly preferably ranges from 0.02 to 0.08 g/Las metal. The film-forming capacity of the surface-treatment bath isusually inadequate at concentrations below 0.01 g/L. On the other hand,no additional improvements in film-forming capacity are normallyobtained at concentrations beyond 2.0 g/L, and the correspondingincrease in the cost of the treatment bath is therefore economicallyunjustified.

The fluoride component can be obtained from acids such as hydrofluoricacid (HF), fluozirconic acid (H₂ ZrF₆), fluotitanic acid (H₂ TiF₆), andthe like, and from the salts of these acids (for example, ammoniumsalts, sodium salts, and the like), but no specific limitations apply tothe particular fluoride selected. (If fluozirconic and/or fluotitanicacids and/or salts thereof are used, these materials are sources of boththe necessary metal content, as described in the paragraph immediatelypreceding this one, and the fluoride.) The fluoride concentration in thesurface-treatment bath preferably ranges from 0.03 to 1.0 g/L, measuredas its stoichiometric equivalent as fluorine, and particularlypreferably ranges from 0.03 to 0.6 g/L as fluorine. The poor reactivityoccurring at concentrations below 0.03 g/L generally prevents theformation of an acceptable coating. At the other end of the range,concentrations above 1 g/L are undesirable due to the deterioration inappearance that results from the greater degree of etching of thealuminiferous metal surface. The most optimal fluoride concentration isdetermined by the concentration of aluminum that elutes from the metaland will therefore vary as a function of this aluminum concentration.This is due to the fact that the fluoride is required at least in partfor the purpose of stabilizing, as aluminum fluoride, the aluminumeluted into the treatment bath. For example, approximately 0.2 g/L offluorine is required per 0.1 g/L of eluted aluminum.

One type of amino-functional water-soluble polyamides used by thepresent invention is exemplified by condensation polyamides fromdicarboxylic acid molecules (e.g., adipic acid, sebacic acid, etc.) anddiamine molecules that contain a tertiary amino group in their mainchains, such as N-(aminoethyl)piperazine, bisN-(aminopropyl)piperazine!, and the like, and by copolyamides of thepreceding with lactams, including lactams that contain a pendanttertiary amino group, e.g., alpha-dimethylamino-epsilon-caprolactam.

A second type of polyamides, whose main chains contain polyoxyalkylenemoieties, are exemplified by polyamides from dicarboxylic acid molecules(e.g., adipic acid, sebacic acid, etc.) and diamine molecules obtainedfrom polyoxyethylene with a molecular weight of approximately 200 to4,000, optionally also including diamines such as hexamethylenediamine,and by copolyamides of the preceding with lactams. In general,polyoxyethylene moieties are preferred over those derived from highermolecular weight epoxides than ethylene oxide.

The surface-treatment bath concentration of water-soluble polyamidemolecules preferably ranges from 0.01 to 2.0 g/L and particularlypreferably ranges is from 0.05 to 0.5 g/L. When the polyamideconcentration falls below 0.01 g/L, coating formation is impeded and anycoating formed also usually will be poorly lubricating. No additionalimprovements in film-forming capacity are generally obtained atpolyamide concentrations beyond 2.0 g/L, and the corresponding increasein the cost of the treatment bath is therefore economically unjustified.

The pH of a surface-treatment bath according to the present inventionshould be from 1.8 to 4.0. The stronger etching that occurs at pH valuesbelow 1.8 makes it difficult for a coating to form, while the formationof highly corrosion-resistant coatings is hindered at pH values inexcess of 4.0. These factors require that the pH be in the range of 1.8to 4.0; the preferred pH range is 2.0 to 3.0. The pH of thesurface-treatment bath can be adjusted through the use of acid, e.g.,phosphoric acid, nitric acid, hydrochloric acid, hydrofluoric acid, andthe like, or alkali, e.g., sodium hydroxide, sodium carbonate, ammoniumhydroxide, and the like.

When treatment bath stability is substantially reduced by alloying metalions, from alloying components such as copper, manganese, and the like,eluting from the workpiece, an at least difunctional organic acid suchas gluconic acid, oxalic acid, etc. and/or other known chelatingagent(s), may advantageously be added to a bath according to thisinvention, in order to chelate this destabilizing component.

Surface-treatment methods according to the present invention will beexplained in detail in the following. While no narrow requirements applyto the treatment temperature and treatment time for thesurface-treatment bath used in the invention method, treatmentpreferably uses the following conditions:

(i) when the surface-treatment bath is applied to the aluminiferousmetal surface by spraying, preferred conditions are contact for 15 to 40seconds at temperatures of 25° C. to 50° C., followed by water rinsing;

(ii) when the metal workpiece is immersed in the surface-treatment bath,preferred conditions are immersion for 15 to 60 seconds at 25° C. to 50°C., followed by water rinsing.

More specifically preferred embodiments of the method according to thepresent invention are given below.

Steps, in Order of Use, in Alternative Preferred Process #1:

1. Degreasing the metal surface (e.g., DI cans) at 40° C. to 80° C. byspraying an acidic or alkaline aqueous based or an organic solvent baseddegreasing composition on the surface for 25 to 60 seconds.

2. Water rinse.

3. Surface treatment, using a bath according to the present invention at25° C. to 50° C. by spraying for 15 to 50 seconds.

4. Water rinse.

5. Rinse with deionized water

6. Drying.

Steps. in Order of Use, in Alternative Preferred Process #2:

1. Degreasing the metal surface (e.g., DI cans) at 40° C. to 80° C. byspraying an acidic or alkaline aqueous based or an organic solvent baseddegreasing composition for 25 to 60 seconds.

2. Water rinse.

3. Phosphate conversion coating treatment at 30° C. to 50° C. byspraying for 8 to 30 seconds.

4. Surface treatment, using a bath according to the present invention at25° C. to 50° C. by spraying for 3 to 30 seconds.

5. Water rinse.

6. Rinse with deionized water

7. Drying.

Steps. in Order of Use, in Alternative Preferred Process #3:

1. Degreasing the metal surface (e.g., DI cans) at 40° C. to 80° C. byspraying an acidic or alkaline aqueous based or an organic solvent baseddegreasing composition for 25 to 60 seconds.

2. Water rinse.

3. Phosphate conversion coating treatment at 30° C. to 50° C. byspraying for 8 to 30 seconds.

4. Water rinse.

5. Surface treatment, using a bath according to the present invention at25° C. to 50° C. by spraying for 3 to 30 seconds.

6. Water rinse.

7. Rinse with deionized water.

8. Drying.

As specified above, 25° C. to 50° C. is the preferred range for thetreatment temperature using a surface-treatment bath according to thepresent invention. Low reactivity at temperatures below 25° C. can leadto failure to form a high quality coating. Most zirconium compounds inthe treatment bath according to this invention become unstable attemperatures above 50° C., which leads to their partial precipitationand can lead to loss of treatment bath stability.

With regard to the treatment times given above, appropriate treatmenttimes in the case of surface-treatment Alternative Preferred Process #1are 15 to 50 seconds. Sufficient reaction does not reliably occur and astrongly corrosion-resistant coating may therefore not be produced attreatment times below 15 seconds. Additional increases in performancebecome uncertain at treatment times in excess of 50 seconds. Aparticularly preferred treatment time range for surface-treatmentAlternative Preferred Process #1 above is 20 to 30 seconds.

Preferred treatment times for surface-treatment Alternative PreferredProcesses 2 and 3 above are 3 to 30 seconds. Sufficient reaction doesnot reliably occur and a strongly corrosion-resistant coating maytherefore not be produced at treatment times below 3 seconds. Additionalincreases in performance become uncertain at treatment times in excessof 30 seconds. A range of 5 to 15 seconds is the particularly preferredtreatment time range for surface-treatment Alternative Processes #2 and#3 above.

The known non-chromium conversion coatings for aluminum can be used asthe phosphate conversion coating in the two-reactive-treatment sequencesof Processes 2 and 3 above. These are specifically exemplified by theconversion coatings described in Japanese Patent Publication Numbers Sho52-131937 131,937/1977!, Sho 58-30344 30,344/1983!, and Sho 57-3931439,314/1982!. When the conversion treatment bath does not contain acomponent (e.g., SO₄ ions) that is detrimental to the effects of thepresent invention, treatment with a bath according to the presentinvention can be executed immediately after conversion treatment withoutan intervening water rinse, as in Alternative Preferred Process 2 above.When the conversion treatment bath does contain such a component,treatment with a bath according to the present invention is preferablycarried out following a water rinse after conversion coating.

This invention will be illustrated in greater detail hereinafter throughworking examples, and the benefits of the invention will be illustratedby comparative examples.

GENERAL CONDITIONS FOR EXAMPLES AND COMPARISON EXAMPLES

1. Substrate metal: Aluminum DI cans

The aluminum DI cans that were surface treated as described below werefabricated by DI-processing of aluminum sheet and then cleaned with ahot aqueous solution of PALKLIN® 500 acidic degreaser, commerciallysupplied by Nihon Parkerizing Company, Ltd.

2. Evaluation methods

(1) Corrosion resistance: Corrosion resistance of the aluminum DI canswas examined by evaluating the extent of blackening after immersion ofthe treated can in boiling water for 30 minutes. Absence of blackeningis the desired result.

(2) Lubricity: Lubricity was evaluated based on the following test usingthe sliding tester depicted in FIGS. 1 (A), (B), and (C). Three of thesurface-treated aluminum DI sample cans were placed on the horizontallypositioned tiltable plate 1 in the sliding tester. Two of the cans,designated as 2a, were loaded with their bottom ends facing to thefront. The remaining single can, designated as 2b, was loaded with itsopen end facing to the front.

The tiltable plate 1 was then tilted at a constant rate of 3° of angleper second by the action of the motor 3. The coefficient of staticfriction was calculated from the angle of inclination, determined fromthe time required until at least one can fell off.

(3) Paint adherence: In order to evaluate the paint adherence, thesurface of the treated can was coated with an epoxy-urea can paint to apaint film thickness of 5 to 7 micrometers, then baked for 4 minutes at215° C. Cellophane tape-peel testing was then carried out on a crossscribed in the evaluation surface using a knife cutter to determineprimary adherence. The sample cans were subsequently immersed for 60minutes in a boiling test solution with the composition given below,after which cellophane tape-peel testing was again carried out todetermine secondary adherence. The adherence was evaluated as thepresence/absence of paint film peeling.

Test solution (simulated juice)

5 g/L of sodium chloride

5 g/L of citric acid

Balance: deionized water

SPECIFIC EXAMPLES Example 1

The surfaces of cleaned aluminum DI cans were subjected to the followingtreatment steps in the sequence given: spraying for 20 seconds withALODINE® 404 zirconium phosphate based conversion coating bath foraluminum DI can applications heated to 35° C. (commercially supplied byNihon Parkerizing Company, Ltd.); spraying for 10 seconds withSurface-treatment Bath 1 having the composition shown below and heatedto 35° C.; rinsing with tap water; spraying for 10 seconds withdeionized water with a specific resistivity of at least 3,000,000ohm-cm; and drying for 2 minutes at 200° C. in a hot-air drying oven.The corrosion resistance and paint adherence of the resulting DI canwere then evaluated. (Note: In all the descriptions of the surfacetreatment baths below, "ppm"=parts per million by weight and the valueshown for fluorine "F"! is the total fluorine from both fluozirconicacid and hydrofluoric acids when both are present.)

    ______________________________________    Surface-treatment Bath 1    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     138         ppm  (PO.sub.4 : 100 ppm)    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     1137        ppm  (Zr: 100 ppm)    20% hydrofluoric acid (HF)                     235         ppm  (F: 170 ppm)    water-soluble polyamide #1                     250         ppm    ______________________________________

pH: 2.5 (adjusted with nitric acid or aqueous ammonia)

The remainder of the Bath was water. Water-soluble polyamide #1 was aterpolymer of adipic acid, N-(aminoethyl)piperazine, and caprolactam.

Example 2

Cleaned aluminum DI cans were subjected to the following treatments inthe sequence given: spraying for 25 seconds with the samesurface-treatment as was used in the first step in Example 1; immersionfor 15 seconds in Surface-treatment Bath 2 having the composition shownbelow and heated to 30° C.; a water rinse and 10-second spray withde-ionized water as in Example 1; and drying for 2 minutes at 200° C. ina hot-air drying oven, The corrosion resistance and paint adherence ofthe resulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 2    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     206         ppm  (PO.sub.4 : 150 ppm)    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     455         ppm  (Zr: 40 ppm)    20% hydofluoric acid (HF)                     210         ppm  (F: 90 ppm)    water-soluble polyamide #1                     150         ppm    ______________________________________

pH: 3.0 (adjusted with nitric acid or aqueous ammonia)

The remainder of the Bath was water.

Example 3

The cleaned aluminum DI cans were subjected to the following treatmentsin the sequence given: spraying for 20 seconds with the samesurface-treatment as was used in the first step in Example 1; sprayingfor 5 seconds with Surface-treatment Bath (3) having the compositionshown below and heated to 45° C.; and a water rinse, de-ionized waterrinse, and drying as in Example 1. The corrosion resistance and paintadherence of the resulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 3    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                    413         ppm  (PO.sub.4 : 300 ppm)    20% fluotitanic acid (H.sub.2 TiF.sub.6)                    683         ppm  (Ti: 40 ppm)    20% hydrofluoric acid (HF)                    262         ppm  (F: 100 ppm)    water-soluble polyamide #2                    200         ppm    ______________________________________

pH: 2.5 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water. Water-soluble polyamide #2 is aterpolymer of adipic acid; an amine terminated polyoxyethylene with thegeneral formula H₂ N--(C₂ H₄ O)_(n) --NH₂, where n represents a positiveinteger with a value such that the polyoxyethylene block represented by(C₂ H₄ O)_(n) has a molecular weight in the range from about 200 to4,000; and caprolactam.

Example 4

The cleaned aluminum DI cans were subjected to the following treatmentsin the sequence given: spraying for 20 seconds with the samesurface-treatment as was used in the first step in Example 1; immersionfor 30 seconds in Surface-treatment Bath 4 having the composition shownbelow and heated to 50° C.; and a water rinse, deionized water rinse,and drying as in Example 1. The corrosion resistance and paint adherenceof the resulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 4    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     138         ppm  (PO.sub.4 : 100 ppm)    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     1137        ppm  (Zr: 100 ppm)    20% hydrofluoric acid (HF)                     235         ppm  (F: 170 ppm)    water-soluble polyamide #2                     100         ppm    ______________________________________

pH: 2.8 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water.

Example 5

The cleaned aluminum DI cans were subjected to the following treatmentsin the sequence given: spraying for 20 seconds with the samesurface-treatment as in the first step of Example 1; spraying for 8seconds with Surface-treatment Bath 5 having the composition shown belowand heated to 35° C.; and a water rinse, deionized water rinse, anddrying as in Example 1. The corrosion resistance and paint adherence ofthe resulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath (5)    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     138         ppm  (PO.sub.4 : 100 ppm)    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     1137        ppm  (Zr: 100 ppm)    20% hydrofluoric acid (HF)                     235         ppm  (F: 170 ppm)    water-soluble polyamide #3                     100         ppm    ______________________________________

pH: 2.5 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water. Water-soluble polyamide #3 was ablock terpolymer of blocks of (i) polycaprolactam, (ii) a copolymer ofadipic acid and N-(aminoethyl)piperazine, and (iii) a copolymer ofadipic acid and an amine terminated polyoxyethylene with the generalformula H₂ N--(C₂ H₄ O)n--NH₂, where n represents a positive integerwith a value such that the polyoxyethylene block represented by (C₂ H₄O)_(n), has a molecular weight in the range from about 200 to 4,000.

Example 6

The cleaned aluminum DI cans were subjected to the following treatmentsin the sequence given: spraying for 30 seconds with PALCOAT®3753surface-treatment, for aluminum DI cans, commercially supplied by NihonParkerizing Company, Ltd. and heated to 50° C.; rinsing with water;spraying for 15 seconds with Surface-treatment Bath 6 having thecomposition shown below and heated to 35° C.; and a water rinse,deionized water rinse, and drying as in Example 1. The corrosionresistance and paint adherence of the resulting DI cans were thenevaluated.

    ______________________________________    Surface-treatment Bath 6    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     412         ppm  (PO.sub.4 : 300 ppm)    20% fluotitanic acid (H.sub.2 TiF.sub.6)                     683         ppm  (Ti: 40 ppm)    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     455         ppm  (Zr: 40 ppm)    20% hydrofluoric acid (HF)                     157         ppm  (F: 80 ppm)    water-soluble polyamide #3                     100         ppm    ______________________________________

pH: 3.0 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water.

Example 7

The cleaned aluminum DI cans were sprayed for 30 seconds withSurface-treatment Bath 7 having the composition shown below and heatedto 25° C., followed by a water rinse, de-ionized water rinse, and dryingas in Example 1. The corrosion resistance and paint adherence of theresulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 7    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     69          ppm  (PO.sub.4 : 50 ppm)    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     455         ppm  (Zr: 40 ppm)    20% hydrofluoric acid (HF)                     25          ppm  (F: 55 ppm)    water-soluble polyamide #3                     50          ppm    ______________________________________

pH: 3.0 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water.

Example 8

The cleaned aluminum DI cans were immersed for 35 seconds inSurface-treatment Bath 8 having the composition shown below and heatedto 40° C., followed by a water rinse, deionized water rinse, and dryingas in Example 1. The corrosion resistance and paint adherence of theresulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 8    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     110         ppm  (PO.sub.4 : 80 ppm)    20% fluotitanic acid (H.sub.2 TiF.sub.6)                     854         ppm  (Ti: 50 ppm)    20% hydrofluoric acid (HF)                     10          ppm  (F: 65 ppm)    water-soluble polyamide #2                     100         ppm    ______________________________________

pH: 3.0 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water.

Comparative Example 1

The cleaned aluminum DI cans were sprayed for 25 seconds with the samesurface-treatment as in the first step of Example 1, followed by a waterrinse, deionized water rinse, and drying as in Example 1. The corrosionresistance and paint adherence of the resulting DI cans were thenevaluated.

Comparative Example 2

The cleaned aluminum DI cans were subjected to the following treatmentsin the sequence given: spraying for 20 seconds with the samesurface-treatment as in the first step of Example 1; spraying for 10seconds with Surface-treatment Bath 9 having the composition shown belowand heated to 35° C.; and a water rinse, deionized water rinse, anddrying as in Example 1. The corrosion resistance and paint adherence ofthe resulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 9    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     138         ppm  (PO.sub.4 : 100 ppm)    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     500         ppm  (Zr: 44 ppm)    20% hydrofluoric acid (HF)                     210         ppm  (F: 95 ppm)    ______________________________________

pH: 3.0 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water.

Comparative Example 3

The cleaned aluminum DI cans were subjected to the following treatmentsin the sequence given: spraying for 25 seconds with the samesurface-treatment as in the first step of Example 1; spraying for 20seconds with Surface-treatment Bath 10 having the composition shownbelow and heated to 35° C.; and a water rinse, deionized water rinse,and drying as in Example 1. The corrosion resistance and paint adherenceof the resulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 10    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                    138         ppm   (PO.sub.4 : 100 ppm)    20% hydrofluoric acid (HF)                    210         ppm   (F: 40 ppm)    water-soluble polyamide #3                    100         ppm    ______________________________________

pH: 3.0 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water.

Comparative Example 4

The cleaned aluminum DI cans were subjected to the following treatmentsin the sequence given: spraying for 25 seconds with the samesurface-treatment as in the first step of Example 1; spraying for 15seconds with Surface-treatment Bath 11 having the composition shownbelow and heated to 35° C.; and a water rinse, deionized water rinse,and drying as in Example 1. The corrosion resistance and paint adherenceof the resulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 11    ______________________________________    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     500         ppm  (Zr: 44 ppm)    20% hydrofluoric acid (HF)                     26          ppm  (F: 60 ppm)    water-soluble polyamide #3                     100         ppm    ______________________________________

pH: 4.5 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water.

Comparative Example 5

The cleaned aluminum DI cans were sprayed for 20 seconds withSurface-treatment Bath 12 having the composition shown below and heatedto 35° C., followed by a water rinse, deionized water rinse, and dryingas in Example 1. The corrosion resistance and paint adherence of theresulting DI cans were then evaluated.

    ______________________________________    Surface-treatment Bath 12    ______________________________________    75% phosphoric acid (H.sub.3 PO.sub.4)                     138         ppm  (PO.sub.4 : 100 ppm)    20% fluozirconic acid (H.sub.2 ZrF.sub.6)                     500         ppm  (Zr: 44 ppm)    20% hydrofluoric acid (HF)                     236         ppm  (F: 100 ppm)    water-soluble polyamide #3                     100         ppm    ______________________________________

pH: 4.5 (adjusted with nitric acid or aqueous ammonia)

The balance of the Bath was water.

The test results from Examples 1 to 8 and Comparative Examples 1 to 5are reported in Table 1. In Examples 1 to 8, the surfaces ofaluminiferous metal were treated with a surface-treatment bath accordingto the present invention by the surface-treatment method according tothe present invention. As the corresponding results in Table 1 makeclear, an excellent corrosion resistance, excellent paint adherence, andexcellent lubricity were obtained in all cases. In contrast to this, apoor lubrication performance in particular was obtained for the productsin Comparative Examples 1 to 5, which used surface-treatment bathsoutside the scope of the invention. Application of the surface-treatmentbath according to the present invention to aluminum DI cans provides thesurface of

                  TABLE 1    ______________________________________                       Paint Adhesion.sup.3    Identification              RtBbBW.sup.1                       Lubricity.sup.2                                 Primary Secondary    ______________________________________    Example 1 ++       ++        no peeling                                         no peeling    Example 2 ++       ++        no peeling                                         no peeling    Example 3 ++       ++        no peeling                                         no peeling    Example 4 ++       ++        no peeling                                         no peeling    Example 5 ++       ++        no peeling                                         no peeling    Example 6 ++       ++        no peeling                                         no peeling    Example 7 ++       ++        no peeling                                         no peeling    Example 8 ++       ++        no peeling                                         no peeling    Comparative              ++       x         no peeling                                         no peeling    Example 1    Comparative              ++       x         no peeling                                         no peeling    Example 2    Comparative              ++       +         no peeling                                         no peeling    Example 3    Comparative              ++       x         no peeling                                         no peeling    Example 4    Comparative              x        +         no peeling                                         no peeling    Example 5    ______________________________________     Footnotes for Table 1     .sup.1 "RtBbBW" = "Resistance to Blackening by Boiling Water" and was     reported on the following scale:     x: entire surface blackened     +: partial blackening     ++: complete absence of blackening.     .sup.2 Lubricity was evaluated on the following scale:     x: coefficient of static friction greater than 1.3     +: coefficient of static friction of 0.9 to 1.3     ++: coefficient of static friction below 0.9.     .sup.3 Paint Adherence, both primary and secondary, was evaluated by the     presence or absence of any detected paint film peeling.

aluminum DI cans with an excellent corrosion resistance and lubricityprior to the painting or printing thereof. This makes possible thehighly desirable effect of supporting an acceleration of themanufacturing line.

The invention claimed is:
 1. An aqueous liquid composition for treatingthe surface of aluminiferous metals with or without dilution with water,said aqueous liquid composition comprising:(A) phosphate ions; (B) acomponent selected from water-soluble zirconium and titanium compounds,in an amount such that the ratio by weight of the stoichiometricequivalent as total zirconium and titanium metal to the weight ofphosphate ions in the composition is from 0.01 to 50; (C) a componentselected from simple and complex fluoride anions, in an amount such thatthe ratio by weight of the stoichiometric equivalent as total fluorineto the weight of phosphate ions in the composition is from 0.01 to 200;and (D) a component selected from polyamides that include moietiesselected from the group consisting of tertiary amino moieties andpolyoxyalkylene moieties, in an amount such that the ratio by weight ofthe polyamides to the weight of phosphate ions in the composition isfrom 0.01 to
 200. 2. A working composition according to claim 1 whichhas a pH value in the range from 1.8 to 4.0 and comprises water and:(A)from 0.01 to 1.0 g/L of phosphate ions; (B) from 0.01 to 0.5 g/L,measured as its total stoichiometric equivalent as zirconium and/ortitanium metal, of a component selected from the group consisting ofwater-soluble zirconium and titanium compounds; (C) from 0.01 to 2.0g/L, measured as its stoichiometric equivalent as fluorine, of acomponent selected from the group consisting of simple and complexfluoride anions; and (D) from 0.01 to 2.0 g/L of a component selectedfrom the group consisting of water-soluble polyamide molecules, each ofwhich contains at least one moiety selected from the group consisting oftertiary amine moieties and polyoxyalkylene moieties.
 3. A compositionaccording to claim 2, wherein the pH value is from 2.0 to 3.0.
 4. Acomposition according to claim 3, wherein the concentration of component(A) is from 0.02 to 0.40 g/L.
 5. A composition according to claim 4,wherein the concentration of component (B) is from 0.02 to 0.08 g/L. 6.A composition to claim 5, wherein the concentration of component (C) isfrom 0.03 to 0.6 g/L.
 7. A composition according to claim 6, wherein theconcentration of component (D) is from 0.05 to 0.5 g/L.
 8. A process fortreating an aluminiferous metal surface to form a coating thereon,comprising a step of contacting the aluminiferous metal surface with acomposition according to claim 7 at a temperature in the range from 25to 50° C. and satisfying one of th following sets of conditions: (i)spraying for 20 to 30 seconds when the surface being treated has notbeen previously phosphate conversion coated; or (ii) spraying for 5 to15 seconds when the surface being treated has been previously phosphateconversion coated.
 9. A process for treating an aluminiferous metalsurface to form a coating thereon, comprising a stop of contacting thealuminiferous metal surface with a composition according to claim 6 at atemperature in the range from 25 to 50° C. and satisfying one of thefollowing sets of conditions: (i) spraying for 20 to 30 seconds when thesurface being treated has not been previously phosphate conversioncoated: (ii) spraying for 5 to 15 seconds when the surface being treatedhas been previously phosphate conversion coated; or (iii) immersion for15 to 60 seconds.
 10. A process for treating an aluminiferous metalsurface to form a coating thereon, comprising a stop of contacting thealuminiferous metal surface with a composition according to claim 5 at atemperature in the range from 25 to 50° C. and satisfying one of thefollowing sets of conditions: (i) spraying for 15 to 40 seconds when thesurface being treated has not been previously phosphate conversioncoated; (ii) spraying for 3 to 30 seconds when the surface being treatedhas been previously phosphate conversion coated; or (iii) immersion for15 to 60 seconds.
 11. A process for treating an aluminiferous metalsurface to form a coating thereon, comprising a stop of contacting thealuminiferous metal surface with a compostion according to claim 4 at atemperature in the range from 25 to 50° C. and satisfying one of thefollowing sets of conditions: (i) spraying for 15 to 40 seconds when thesurface being treated has not been previously phosphate conversioncoated; (ii) spraying for 3 to 30 seconds when the surface being treatedhas been previously phosphate conversion coated; or (iii) immersion for15 to 60 seconds.
 12. A process for treating an aluminiferous metalsurface to form a coating thereon, comprising a step of contacting thealumlnlferous metal surface with a composition according to claim 3 at atemperature in the range from 25 to 50° C. and satisfying one of thefollowing sets of conditions: (i) spraying for 15 to 40 seconds when thesurface being treated has not been previously phosphate conversioncoated; (ii) spraying for 3 to 30 seconds when the surface being treatedhas been previously phosphate conversion coated; or (ii) immersion for15 to 60 seconds.
 13. A process for treating an aluminiferous metalsurface to form a coating thereon, comprising a step of contacting thealuminiferous metal surface with a composition according to claim 2 t atemperature in the range from 25 to 50° C.